Determination of the Deprotonation Constants of Seleno-DL-cystine and Seleno-DL-methionine and Implication to their Separation by HPLC

cited By 11International audienceWe have determined the deprotonation constants (pKa) of seleno-DL-cystine and seleno-DL-methionine together with those of DL-cystine and DL-methionine for comparison, by potentiometric measurements. In the case of seleno-DL-cystine, the difference between the pKa values for the two amino groups was found to be only slightly lower than that observed for DL-cystine itself. In contrast, the difference between the two pKa values for the carboxylic groups was found to be much smaller for seleno-DL-cystine than for DL-cystine. In both seleno-amino-acids, the zwitterionic species appear to be dominant in the pH range between 4 and 7, while positively charged protonated species are found to be present at pH values lower than 4. Based on a knowledge of the ionic species distributions as a function of pH, we have proposed an interpretation for the Chromatographic separation of selenocystine and selenomethionine by HPLC. © 1997 by John Wiley & Sons, Ltd

Genomic Designing for Climate-Smart Tomato

Tomato is the first vegetable consumed in the world. It is grown in very different conditions and areas, mainly in field for processing tomatoes while fresh-market tomatoes are often produced in greenhouses. Tomato faces many environmental stresses, both biotic and abiotic. Today many new genomic resources are available allowing an acceleration of the genetic progress. In this chapter, we will first present the main challenges to breed climate-smart tomatoes. The breeding objectives relative to productivity, fruit quality, and adaptation to environmental stresses will be presented with a special focus on how climate change is impacting these objectives. In the second part, the genetic and genomic resources available will be presented. Then, traditional and molecular breeding techniques will be discussed. A special focus will then be presented on ecophysiological modeling, which could constitute an important strategy to define new ideotypes adapted to breeding objectives. Finally, we will illustrate how new biotechnological tools are implemented and could be used to breed climate-smart tomatoes